Enable XFA by default in the viewer, and components/ examples (issue 13968)

Given that https://bugzilla.mozilla.org/show_bug.cgi?id=1727396 has now landed, it should now be OK to make this change.

web/text_layer_builder.js

@@ -244,6 +244,7 @@ class DefaultTextLayerFactory {
       viewport,
       enhanceTextSelection,
       eventBus,
+      highlighter,
     });
   }
 }